How to Weld a Cast Iron Marine Engine with 77 Electrode

132 How to Weld a Cast Iron Marine Engine

Muggy Weld customer Scott Yeges recently pulled this cast iron marine engine from a scrapyard and noticed the starter mount was broken at the corner. Unfortunately, this is a common occurrence. Whether the engine is mismounted or it’s simply knocked over and the mounting brackets damaged, Muggy Weld employees frequently receive calls asking how to repair damaged starter mount brackets. Thanks to Scott, we can now share his story for our customers’ benefit.

In this video you’ll see the videos Scott shared of his welding process, and this is Scott’s accompanying narrative.

This used motor from a wrecking yard appeared clean and tight. I did not trust the scrapyard to repair the broken starter mount bracket, so I purchased 77 electrode and attempted to weld the cast iron myself.

I used a 40 year old Sears and Roebuck buzzbox without any problems. I preheated the engine a little prior to welding.

The first pass flowed well. I welded roughly an inch at a time. The Muggy rod built up well, no issues at all.

I used a needle scaler to remove slag. Very little porosity. Finished nicely! Repaired it in my garage!

Thanks, Muggy Weld; your welding rod is incredible. It made for an easy repair for something I was dreading. And I have already told some guys about your product.

Thanks again,

Scott Yerges

And thank you, Scott, for sharing these photos with our customers. Scott further noted:

I found the engine, fixed the problem after I identified it. I then used the swing set I built to install the motor. Then sent my son and family back home with a great running boat.


Be sure to bevel the crack with a grinder or Demel tool prior to welding, to enable the 77 rod to anchor to the base metal.


Note:  Please observe all AWS Safety & Health Guidelines when using Muggy Weld products.